The Metrology Light Source (MLS) is a 630 MeV electron storage ring as a synchrotron radiation source for the terahertz (THz) to the extreme UV spectral range. Its upgrade project MLS II is defined as a compact 0.8 GeV storage ring with multiple operation modes, which pursues lower emittance (<50 nm) in standard user mode and preserves the strong capability of MLS to manipulate the momentum compaction and its higher-order terms for short-bunch mode. This paper presents the lattice options based on double-bend achromat (DBA) and quadruple-bend achromat (QBA). The linear optics and nonlinear beam dynamics of both lattices were investigated.

The concept of steady-state microbunching (SSMB) as a new scheme for the production of high power synchrotron radiation has been demonstrated at the Metrology Light Source in Berlin-Adlershof (MLS) [1]. At the MLS the same undulator section is used for the generation of the micro-structures onto the electron bunch as well as for the detection of the resulting coherent radiation from the micro-bunches one turn later. Due to the enormous difference in the pulse energy of the micro-bucket generating laser and the coherent undulator pulses showing up 160 ns later, the detection is not straightforward. We show in detail the detection scheme, mostly based on fast optical shutters, and the triggering scheme of the experiment. Ideas for further improvements are discussed. [1] X. Deng et al., Nature, Volume 590, Issue 7847

Steady-state microbunching (SSMB) is envisioned to enable the generation of high-power coherent synchrotron radiation at an electron storage ring for wavelengths up to the extreme ultraviolet. The underlying mechanism has been shown to be viable in a proof-of-principle (PoP) experiment at the Metrology Light Source (MLS) in Berlin\*. An enhanced detection scheme allows systematic studies of the conditions needed for the creation of microbunches within the continuing PoP experiment\*\*. It was found that the generation of coherent radiation from microbunches is favored in specific nonlinear longitudinal phase space structures, known as “alpha buckets”, which arise when the momentum compaction function becomes dominated by higher order terms. We present the most recent experimental results and their interpretation as well as accompanying simulation results.